Updating Go impl to use amqp uri from env

sylvilagus/go/src/meatballhat.com/sylvilagus-chapter02-hello-world-consumer/main.go

@@ -10,7 +10,7 @@ import (
 )
 
 func main() {
-	connection, err := amqp.Dial("amqp://guest:guest@localhost:5672")
+	connection, err := amqp.Dial(sylvilagus.AMQP_URI)
 	if err != nil {
 		log.Fatal("Failed to connect!: ", err)
 	}

sylvilagus/go/src/meatballhat.com/sylvilagus-chapter02-hello-world-producer/main.go

@@ -18,7 +18,7 @@ func main() {
 
 	msgBody := string(os.Args[1])
 
-	connection, err := amqp.Dial("amqp://guest:guest@localhost:5672")
+	connection, err := amqp.Dial(sylvilagus.AMQP_URI)
 	if err != nil {
 		log.Fatal("Failed to connect!: ", err)
 	}

sylvilagus/go/src/meatballhat.com/sylvilagus/hello.go

@@ -2,12 +2,21 @@ package sylvilagus
 
 import (
 	"log"
+	"os"
 )
 
 import (
 	"github.com/streadway/amqp"
 )
 
+var AMQP_URI = os.Getenv("SYLVILAGUS_AMQP_URI")
+
+func init() {
+	if len(AMQP_URI) < 1 {
+		log.Fatal("SYLVILAGUS_AMQP_URI is not defined!")
+	}
+}
+
 func CreateHelloTopology(connection *amqp.Connection) (*amqp.Channel, error) {
 	channel, err := connection.Channel()
 	if err != nil {